You'll need to use B::Deparse for this; for instance:

use B::Deparse;
use Data::Dumper;

my $deparse = B::Deparse->new;
print $deparse->coderef2text( sub{print 'Yeah'} )
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As for Data::Dumper, the newest version (the one that came with 5.8.0; if you don't have it, get it from the CPAN) has an option called Deparse; turn it on, and it will use B::Deparse to stringify coderefs for you:

my $test = {
  test => 1,
  code => sub { print 'Yeah'; },
  aref => [ qw(1 2 3 4 5) ],
};
$Data::Dumper::Deparse = 1;
print Dumper($test);
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